Photographic pigmentary printing paper



Patented Jan. 26, "1926.

"UNITED STATES 1,571,103. PATENT OFFICE. 7

JOSEPH SURY, OF WYNEGHEM, NEAR ANTWERP, BELGIUM.

1K0 Drawing.

To all whom it may concern:

Be it known that I, JOSEPH SURY, a subject of the King of the Belgians, residing at VVyneghem, near Antwerp, in the Kingdom of Belgium, have invented certaln new and useful Improvements in Photo raph c Pigunentary Printing Paper, of w ich the following is a specification.

The present invention'has for ts ob ect a photographic paper capable of rece1v1ng and retaining, after development, powdered plgrhents of all colours.

Known pigmentary photographic papers, possess various inconveniences amongst which may be mentioned the absence of vis1- bility of the image after the exposure; the

necessity for effecting a transfer on to a provisional supportin the case of a paper having a thick emulsion and on the other hand the necessity {for reat exactness in working in the case 0 a paper having a thin emulsion to avoid producing excessive 1nsoluhilityof the blacks.

The ur use of the. present inventionis to reme y these inconveniences that is to say to provide apignientary paper giving a visible picture at the time of exposure conse quently not necessitati the use of a photometer, the said paper being developed without previous transfer and bein capable of receiving "and retaining after evelopment, powdered pigments of all colours.

Th improved paper is manufactured by incorporating with a colloidal emulsion a temporary colouring matter serving as guide for developing, said colouring matter being substance, for instance barium sulfate, kaolin, or the like, which, incorporated with the colloidal emulsion, prevents contraction or sinking of the moist emulsion after the dis appearance of .the blue colouring matter so as to form as it were infinitesimalpillars Application filed May 26,

PEOTOGRAPHIG PIGMENTARY PRINTING PAPER.

1924. Serial No. 716,049.

and arches which during the drying maintain open the 'HliCIOSCOPlC; cavities produced by the disappearance of the colouring matter and .the gaseous discharge.

In order to carry out the invention a paper preferably thickly sized, is coated with an emulsion of one or more colloids, for instance gelatine, gum arabic, albumen, or a mixture of these (substances in which hasbee'n incorporated a certain quantity of powdered'barium sulfate or kaolin towhich is added aluminum sodium silicate and sodium pentasulfid.

This mixture is spread by any means over.

the non-porous surface of the paper and is allowed to dry.

When the paper isrequired for use it is sensitised by means of an aqueousor aqueoalcoholic solution of an alkali bichromate.

. After drying the. paper is exposed under a negative and the resulting'print can be inspected owing to the appearance of the image resulting from the action of the light on the bichromate. After printing the picture is developed in cold or hot water then decoloured in a diluted solution of hydrochloric acid. Under the action of this bath,

the blue colouring matter dissolves with gaseous production of hydrogen'sulfid and sulphurousacid. This 1 gaseous discharge by producing an eifervescencerenders the layer of pasty colloidal emulsion spongyth barium sulfate (or the kaolin) contained in i the. emulsion being present therein in the form of infinitesimal illars and archesv keeping open, during rying, the microance of the colouring matter and the gaseous eifervescenceas previously described.

the paper is capable ,owing to its porosity of retaining any powdered pigment applied on its surface. This pigment not-being fixed by an adhesive can be transferred by vslight pressure on to a sheet of paper coated with an adhesive or the'pigment canbe fixed on the original print similarly to fixing a charcoal drawing. 1

Alternatively the dried porous emulsion, when pressed hard against a plate of sufplate. anetching capable of being inked with fatty inks and a number of copies'can be printed therefrom by means of 'a printing press.

scopic cav1t1es produced by the disappear-' .95 After drying, the emulsion which coats .ficiently soft metal will produce on the metal I I The improved paper'hac'uotonl y the 811-" l vantag of allowing the exposure to be gauged owingto the visibility of the image,

thus rendering the use of a photometer unnecessary, but further allows an easy transfer of the image which is particularly ad vantageous in colour photograph wherein three selected colour images (ye low, .red, blue) are superposed by transfer method on to a support to reproduce the natural colours of the object photographed.

' What I claim is:

1. A pigmentary photographic printing paper, characterized by a colloidal coating, containing a temporary colouring matter permeable to li ht and capableof being dissolved by a di uted acid with gaseous discharge whereby the colloidal coating is rendered spongy. 2. A pigmentary paper, as in claim 1, wherein the temporary colouring matter is composed of aluminum sodium silicate and sodium pentasulphide mixed with'a powdered inert white substance, whereby to provide means for kee ing open the cavlties produced in the colloidal coating by the dis solving' of the colouring matter and the gaseous discharge produced by a solution of hydrochloric acld.

In testimony whereof I have aflixed my signature.

JOSEPH SURY. 

